1. Technical Field
The present disclosure relates to a white light emitting diode (LED).
2. Discussion of Related Art
LEDs have higher energy conversion efficiency, higher radiance (i.e., they emit a larger quantity of light per unit area), longer lifetime, higher response speed, generate less heat, and have better reliability than conventional light sources. Therefore, LED modules are widely used as light sources in optical imaging systems, especially, white LED.
A conventional white LED mainly includes the following two different structures. One kind of the conventional white LED includes a blue LED structure and a yellow fluorescent powder coated on the blue LED structure. Parts of blue light emitted from the blue LED structure will be absorbed by the yellow fluorescent powder to emit yellow light. The other parts of blue light and the yellow light will mix to emit the white light. However, the efficiency of this kind of the white LED is low. Another kind of the conventional white LED includes a blue LED chip, a green LED chip and a red LED chip stacked together. The blue light, green light and red light emitted from the blue LED chip, the green LED chip and the red LED chip respectively will mix to form the white light. However, a method for making this kind of the white LED is complicated and costly.
What is needed, therefore, is to provide a light emitting diode, which can overcome the above-described shortcomings.